Scanning Probe Microscope and Scanning Method Thereof

ABSTRACT

A scanning probe microscope has a cantilever having a probe at a tip of the cantilever, a driving unit that performs a separating operation for separating one of the sample and the probe from the other at a speed exceeding a response speed of the cantilever from a state where the probe is in contact with the surface of the sample, a determination unit that determines that the probe is separated from the surface of the sample when vibration of the cantilever at a predetermined amplitude is detected at a resonant frequency of the cantilever during the separating operation, and a driving control unit that stops the separating operation when the determination unit determines that the probe is separated from the surface of the sample and relatively moves the probe and the sample to a position where the probe is located on a next measuring point of the sample.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority from Japanese Patent Application No.2017-063530, filed on Mar. 28, 2017, the entire subject matters of whichis incorporated herein by reference.

BACKGROUND 1. Field of the Invention

The present disclosure relates to a scanning probe microscope and ascanning method thereof.

2. Background Art

A scanning probe microscope is known in which a probe is continuouslyscanned on a surface of a sample while keeping an interaction (forexample, amplitude of a cantilever or deflection of the cantilever)constant between the probe formed on a tip of the cantilever and thesample, thereby measuring an uneven shape of the sample surface (SeeJP-A-H10-62158.). In the scanning probe microscope disclosed inJP-A-H10-62158, since the probe and the sample are always in contactwith each other, abrasion of the probe or damage of the sample mayoccur.

Meanwhile, JP-A-2001-33373 and JP-A-2007-85764 disclose a technique ofintermittently scanning the sample surface by bringing the probe and thesample surface into contact with only a plurality of preset measuringpoints on the sample surface and measuring an uneven shape of the samplesurface. In this intermittent measurement method, the probe is broughtclose to the surface of the sample from a position above thepredetermined measuring point, and a height of the probe is measuredwhen the probe is come in contact with the surface of the sample. Then,when the measurement is completed, the probe in contact with the surfaceof the sample is separated from the surface of the sample by the preset“separation distance” and is moved up to a position above the nextmeasuring point. In this way, according to the intermittent measurementmethod, since the probe and the sample surface are in contact with eachother only at the measuring point, as compared with JP-A-H10-62158, boththem are in contact with each other at a minimum, and thus abrasion ofthe probe or damage of the sample can be reduced.

In particular, when the intermittent measurement method is carried outin a so-called contact mode in which the shape of the surface ismeasured while controlling the deflection of the cantilever to beconstant, the scanning probe microscope repeatedly performs in general astep of bringing the probe close to the surface of the sample andmeasuring a height of the probe by determining that the probe is incontact with the surface of the sample when a force (deflection) appliedto the cantilever becomes equal to or more than a certain value and astep of separating the probe from the sample by the “separationdistance” and moving the probe up to the position above the nextmeasurement position, thereby intermittently scanning the surface of thesample in general.

In order to separate the probe from the sample, the above-described“separation distance” needs to be set such that a force calculated bythe product of a spring constant of the cantilever and the separationdistance is larger than the adsorption power between the probe and thesample. However, the adsorption power between the probe and the samplevaries depending on positions on the surface of the sample. Therefore,in the case of the sample in which the adsorption power between theprobe and the sample differs greatly depending on the positions on thesurface of the sample, the separation distance is set to have asufficient margin so that the separation reliably occurs even at theposition of the maximum adsorption power. Further, this value is avalue, which indicates a separation distance, set to have the allowancebased on experience of an operator in consideration of non-contact witha convex portion of the sample during movement to an upper positionafter separation of the probe from a certain measuring point.Nevertheless, in the case where the adsorption power is larger than apredicted value or the convex portion exists, the probe and the sampleare brought into contact with each other and are damaged mutuallybecause the separation distance is insufficient.

When the separation distance is set to a large value with a sufficientmargin, the movement path to the position above the next measuring pointbecomes longer. As a result, the time for measuring the uneven shape ofthe surface of the sample becomes long as a whole, and the measurementefficiency of the uneven shape on the surface of the sample decreases.

SUMMARY

The object of the present disclosure is to provide a scanning probemicroscope and a scanning method thereof that enable to improvemeasurement efficiency of an uneven shape on a surface of a sample.

According to an exemplary embodiment of the present disclosure, there isprovided a scanning probe microscope in which a probe is brought intocontact with a surface of a sample and the probe intermittently scansthe surface of the sample, comprising:

a cantilever having the probe at a tip of the cantilever;

a driving unit configured to perform a separating operation forseparating one of the sample and the probe from the other in a directionthat the sample and the probe come apart each other, at a speedexceeding a response speed of the cantilever, from a state where theprobe is in contact with the surface of the sample;

a determination unit configured to determine that the probe is separatedfrom the surface of the sample in a case where vibration of thecantilever at a predetermined amplitude is detected at a resonantfrequency of the cantilever during the separating operation; and

a driving control unit configured to stop the separating operation bythe driving unit at a moment of time when the determination unitdetermines that the probe is separated from the surface of the sampleand relatively move the probe and the sample to a position where theprobe is located on a next measuring point of the sample.

According to another exemplary embodiment of the present disclosure,there is provided a scanning probe microscope in which a probe isbrought into contact with a surface of a sample and the probe scans thesurface of the sample, comprising:

a cantilever having the probe at a tip of the cantilever;

a driving unit configured to perform a separating operation forseparating one of the sample and the probe from the other in a directionthat the sample and the probe come apart each other, at a speed notexceeding a response speed of the cantilever, from a state where theprobe is in contact with the surface of the sample;

a determination unit configured to determines separation of the probewith respect to the surface of the sample, based on a speed change in adeflection direction of the cantilever, during the separating operation;and

a driving control unit configured to stop the separating operation bythe driving unit at a moment of time when the determination unitdetermines that the probe is separated from the surface of the sampleand relatively move the probe and the sample to a position where theprobe is located on a next measuring point of the sample.

According to another exemplary embodiment of the present disclosure,there is provided a scanning probe microscope in which a probe isbrought into contact with a surface of a sample and the probeintermittently scans the surface of the sample, comprising:

a cantilever having the probe at a tip of the cantilever;

a driving unit configured to perform a separating operation forseparating one of the sample and the probe from the other, from a statewhere the probe is in contact with the surface of the sample;

a determination unit configured to determine separation of the probewith respect to the surface of the sample, based on a change inamplitude of vibration in the cantilever or a change in vibrationfrequency of the vibration, during the separating operation; and

a driving control unit configured to stop the separating operation bythe driving unit at a moment of time when the determination unitdetermines that the probe is separated from the surface of the sampleand relatively move the probe and the sample to a position where theprobe is located on a next measuring point of the sample.

According to another exemplary embodiment of the present disclosure,there is provided a scanning probe microscope in which a probe isbrought into contact with a surface of a sample and the probeintermittently scans the surface of the sample, comprising:

a cantilever having the probe at a tip of the cantilever;

a driving unit configured to perform a separating operation forseparating one of the sample and the probe from the other, from a statewhere the probe is in contact with the surface of the sample;

an oscillation unit configured to relatively vibrate the sample and thecantilever at a predetermined frequency during the separating operation;

a determination unit configured to determine separation of the probewith respect to the surface of the sample, based on a change inamplitude at the predetermined frequency in a deflection direction or atwist direction of the cantilever, during the separating operation; and

a driving control unit configured to stop the separating operation bythe driving unit at a moment of time when the determination unitdetermines that the probe is separated from the surface of the sampleand relatively move the probe and the sample to a position where theprobe is located on a next measuring point of the sample.

According to another exemplary embodiment of the present disclosure,there is provided a scanning probe microscope in which a probe isbrought into contact with a surface of a sample and the probeintermittently scans the surface of the sample, comprising:

a cantilever having the probe at a tip of the cantilever;

a driving unit configured to perform a separating operation forseparating one of the sample and the probe from the other, from a statewhere the probe is in contact with the surface of the sample;

an oscillation unit configured to excites the cantilever at a resonantfrequency during the separating operation;

a determination unit configured to determine separation of the probewith respect to the surface of the sample, based on a phase differencebetween a phase of vibration in a deflection direction or a twistdirection of the cantilever and a phase of the resonant frequencyexcited by the oscillation unit, during the separating operation; and

a driving control unit configured to stop the separating operation bythe driving unit at a moment of time when the determination unitdetermines that the probe is separated from the surface of the sampleand relatively move the probe and the sample to a position where theprobe is located on a next measuring point of the sample.

According to another exemplary embodiment of the present disclosure,there is provided a probe scanning method of a scanning probe microscopein which a probe is brought into contact with a surface of a sample andthe probe intermittently scans the surface of the sample, the methodcomprising:

a driving step, in a cantilever having the probe at a tip of thecantilever, of performing a separating operation for separating one ofthe sample and the probe from the other in a direction that the sampleand the probe come apart each other, at a speed exceeding a responsespeed of the cantilever, from a state where the probe is in contact withthe surface of the sample;

a determining step of determining that the probe is separated from thesurface of the sample in a case where vibration of the cantilever at apredetermined amplitude is detected at a resonant frequency of thecantilever during the separating operation; and a driving control stepof stopping the separating operation by the driving step at a moment oftime when it is determined in the determining step that the probe isseparated from the surface of the sample and relatively moving the probeand the sample to a position where the probe is located on a nextmeasuring point of the sample.

According to another exemplary embodiment of the present disclosure,there is provided a probe scanning method of a scanning probe microscopein which a probe is brought into contact with a surface of a sample andthe probe scans the surface of the sample, the method comprising:

a driving step, in a cantilever having the probe at a tip of thecantilever, of performing a separating operation for separating one ofthe sample and the probe from the other in a direction that the sampleand the probe come apart each other, at a speed not exceeding a responsespeed of the cantilever, from a state where the probe is in contact withthe surface of the sample;

a determining step of determining separation of the probe with respectto the surface of the sample, based on a speed change in a deflectiondirection of the cantilever, during the separating operation; and

a driving control step of stopping the separating operation by thedriving step at a moment of time when it is determined in thedetermining step that the probe is separated from the surface of thesample and relatively moving the probe and the sample to a positionwhere the probe is located on a next measuring point of the sample.

According to the present disclosure, it is possible to avoid damage of aprobe and a sample while eliminating the troublesome of consideration ofunknown adsorption power or a height of a convex on a surface of thesample in setting of a separation distance. Therefore, it is possible toimprove measurement efficiency of an uneven shape on the surface of thesample

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings:

FIG. 1 is a diagram showing an example of a schematic configuration of ascanning probe microscope A according to a first embodiment;

FIG. 2 is a perspective diagram showing a sample S having a slope and acantilever 2 according to the first embodiment;

FIG. 3 is a diagram showing a flow of an intermittent measurement methodof the scanning probe microscope A according to the first embodiment;

FIG. 4 is a diagram illustrating a first range and a second rangeaccording to the first embodiment;

FIGS. 5A and 5B are diagrams showing a state of the cantilever 2 in acase where the sample S is moved in a direction being separated from theprobe 2 a at a normal speed;

FIGS. 6A and 6B are diagrams showing a state of the cantilever 2 in aseparating operation (in a case where the sample S is moved in thedirection being separated from the probe 2 a at a speed exceeding aresponse speed of the cantilever 2) according to the first embodiment;

FIG. 7 is a flowchart of a separation determination process according tothe first embodiment;

FIG. 8 is a diagram showing an example of a schematic configuration of aZ-direction driving device 51 according to the first embodiment;

FIG. 9 is a diagram showing an example of a schematic configuration of ascanning probe microscope B according to a second embodiment;

FIGS. 10A and 10B are graphs showing a speed change of the cantilever 2in a deflection direction, in a separating operation according to thesecond embodiment;

FIGS. 11A and 11B are diagrams showing a state of the cantilever 2 inthe separating operation (in a case where the sample S is moved in thedirection being separated from the probe 2 a at a speed equal to orlower than the response speed of the cantilever 2) according to thesecond embodiment;

FIG. 12 is a flowchart of a separation determination process accordingto the second embodiment;

FIG. 13 is a diagram showing an example of a schematic configuration ofa scanning probe microscope C according to a third embodiment;

FIGS. 14A and 14B are diagrams showing a state of the cantilever 2 in aseparating operation according to the third embodiment (FIG. 14A shows acase of vibrating the cantilever 2 in the deflection direction and FIG.14B shows a case of vibrating the cantilever 2 in a twist direction);

FIG. 15 is a diagram showing an example of a schematic configuration ofa scanning probe microscope D according to a fourth embodiment;

FIGS. 16A and 16B are diagrams illustrating a method of detecting adecrease amount of an amplitude in a non-resonant frequency in adeflection direction or a twist direction, in a cantilever according tothe fourth embodiment (FIG. 16A shows a case of vibrating the cantileverin the deflection direction and FIG. 16B shows a case of vibrating thecantilever in the twist direction);

FIGS. 17A and 17B are diagrams illustrating a method of detecting anincrease amount of an amplitude in a resonant frequency in a deflectiondirection or a twist direction in the cantilever according to the fourthembodiment (FIG. 17A shows a case of vibrating the cantilever in thedeflection direction and FIG. 17B shows a case of vibrating thecantilever in the twist direction);

FIGS. 18A and 18B are diagrams illustrating a method of detecting adecrease amount of an amplitude in a resonant frequency in a deflectiondirection or a twist direction, in the cantilever according to thefourth embodiment (FIG. 18A shows a case of vibrating the cantilever inthe deflection direction and FIG. 18B shows a case of vibrating thecantilever in the twist direction);

FIG. 19 is a diagram showing an example of a schematic configuration ofa scanning probe microscope E according to a fifth embodiment; and

FIGS. 20A and 20B are diagrams illustrating a separation determinationprocess according to the fifth embodiment.

DETAILED DESCRIPTION

A scanning probe microscope according to a first embodiment of thepresent disclosure is a scanning probe microscope using a method inwhich a probe is caused to contact with a sample surface therebyscanning the sample surface with the probe, that is, an intermittentmeasurement method.

Hereinafter, the scanning probe microscope according to the firstembodiment of the present disclosure will be described with reference todrawings. In the drawings, the same or similar parts are denoted by thesame reference signs, and redundant description may be omitted in somecases. In addition, shapes and sizes of elements in the drawings may beexaggerated for a clearer explanation.

First Embodiment

FIG. 1 is a diagram showing an example of a schematic configuration of ascanning probe microscope A according to a first embodiment. As shown inFIG. 1, the scanning probe microscope A includes a cantilever 2, asample stage 4, a movement driving unit 5, a displacement detecting unit6, and a control device 7.

The cantilever 2 includes a probe 2 a on a tip. The cantilever 2 isconfigured such that a base end thereof is fixed and the tip is a freeend. The cantilever 2 is an elastic lever member having a small springconstant K. When the probe 2 a of the tip and the surface of a sample S(hereinafter, referred to as a “sample surface”) contact with eachother, deflection occurs according to pressing force by which the probe2 a of the tip presses the sample surface.

In addition, in a case where the probe 2 a of the tip and the samplesurface contact with each other and the sample surface has aninclination, a twist or a deflection according to the inclination of thesample surface and a support reaction of a supporting point that is acontact point between the probe 2 a of the tip and the sample surfaceoccurs on cantilever 2.

The movement driving unit 5 moves the probe 2 a and sample S relative toeach other in a three-dimensional direction. The movement driving unit 5includes Z-direction driving device 51 (a driving unit) and anXY-scanner (a scanner) 52.

The sample stage 4 is mounted on the Z-direction driving device 51. Thesample S is placed on the sample stage 4 so as to be disposed to facethe probe 2 a of cantilever 2.

The Z-direction driving device 51 moves the sample stage 4 in adirection (a Z direction) perpendicular to a horizontal surface. Forexample, the Z-direction driving device 51 is a piezoelectric element.

The Z-direction driving device 51 performs an approaching operation bywhich the sample surface approaches the probe 2 a or a separatingoperation by which the sample S is moved in a direction being separatedfrom the probe 2 a by moving the sample stage 4 in the Z directionthrough controlling from the control device 7.

The XY scanner 52 moves the probe 2 a and sample S relative to eachother in an XY direction through a control from the control device 7. InFIG. 1, a plane parallel with a surface of the sample stage 4 is ahorizontal surface, and here, is defined as an XY plane by orthogonaltwo axes X and Y. For elevation stage, the XY scanner 52 is apiezoelectric element.

A Z-direction driving device 51 and the XY scanner 52 may have anydisposition relationship as long as a configuration thereof is capableof relative scanning for observing a three-dimensional shape.

The displacement detecting unit 6 detects a deflection amount and atwist amount of the cantilever 2. In the first embodiment, a case wherethe displacement detecting unit 6 detects the deflection amount and thetwist amount of the cantilever 2 using an optical lever type will bedescribed.

The displacement detecting unit 6 includes an irradiation unit 61 and alight detection unit 62.

The optical irradiation unit 61 irradiates a reflection surface (notillustrated) formed on a back surface of the cantilever 2 with laserlight L1.

The light detection unit 62 receives the laser light L2 reflected by thereflection surface. The light detection unit 62 is a photodetectorincluding a four-divided light receiving surface 27 that receives thelaser light L2 reflected by the back surface. That is, an optical pathis adjusted (in general, to be in the vicinity of the center of thelight receiving surface 27) such that the laser light L2 reflected bythe back surface of the cantilever 2 is incident to a plurality of lightreceiving surfaces 27, that is divided into four sections, of the lightdetection unit 62.

Hereinafter, a method of detecting the deflection amount and the twistamount of the cantilever 2 according to the first embodiment will bedescribed with reference to FIGS. 1 and 2. FIG. 2 is a perspectivediagram showing a sample S having a slope and the cantilever 2.

In a case where the probe 2 a and sample surface contact with eachother, a displacement occurs on the cantilever 2 in either or both ofthe Z direction and a Y direction. In the first embodiment, adisplacement of the cantilever 2 occurring in the Z direction isreferred to as a deflection amount and a displacement of the cantilever2 occurring in the Y direction is referred to as a twist amount. Forexample, in an initial state, an incidence spot position of the laserlight L2 reflected in a state where a force is not applied to the probe2 a, in the light receiving surface 27 of the light detection unit 62,is assumed as the center position of the light receiving surface 27. Thestate where a force is not applied to the probe 2 a is, for example, isa state of a not-deformed cantilever (hereinafter, referred to as “freestate”) in which the probe 2 a and the sample surface do not contactwith each other.

In a contact mode, when the probe 2 a and sample surface contact witheach other, a force is applied to the probe 2 a. Therefore, thedeflection amount and the twist amount is generated in the cantilever 2.Accordingly, a reflection spot position of the laser light L2 reflectedby the back surface of the cantilever 2 where the deflection amount orthe twist amount is generated is displaced from the center position.Therefore, the scanning probe microscope A becomes possible to detect amagnitude and a direction of the force applied to the probe 2 a bycatching a movement direction of the spot position in the lightreceiving surface 27 of the light detection unit 62.

For example, in FIG. 1, in a case where the twist amount is generated inthe cantilever 2, it is possible to catch a change in the spot positionin an a direction in the light receiving surface 27 of the lightdetection unit 62. In addition, in a case where the deflection amount isgenerated in the cantilever 2, it is possible to catch a change in thespot position in a β direction in the light receiving surface 27.

Here, a change amount of the spot position from the center positiondepends on the twist amount or the deflection amount. Specifically, in acase where the cantilever 2 is deflected in a +Z direction, thereflection spot of the laser light L2 in the light receiving surface 27of the light detection unit 62 changes in a +β direction. In addition,in a case where the cantilever 2 is deflected in a −Z direction, thereflection spot of the laser light L2 in the light receiving surface 27of the light detection unit 62 changes in a −β direction. On the otherhand, in a case where the twist amount in a +Y direction is generated inthe cantilever 2, the reflection spot position of the laser light L2 inthe light receiving surface 27 of the light detection unit 62 changes ina +a direction. In addition, in a case where the twist amount in a −Ydirection is generated in the cantilever 2, the reflection spot of thelaser light L2 in the light receiving surface 27 of the light detectionunit 62 changes in a −α direction.

The light detection unit 62 outputs a first detection signal accordingto the reflection spot position of the laser light L2 in ±Z directionsof the light receiving surface 27 to the control device 7. That is, thefirst detection signal is a DIF signal (the deflection signal) accordingto the deflection amount of the cantilever 2. In addition, the lightdetection unit 62 outputs a second detection signal according to thereflection spot position of the laser light L2 in ±Y directions of thelight receiving surface 27 to the control device 7. That is, the seconddetection signal is an FFM signal (the twist signal) according to thetwist amount of the cantilever 2.

Next, the control device 7 according to the first embodiment will bedescribed.

As shown in FIG. 1, the control device 7 includes a determination unit42, a driving control unit 43, and a measurement unit 44.

The determination unit 42 determines whether the probe 2 a has contactedwith the sample surface based on the first detection signal and thesecond detection signal which are output from the light detection unit62. In the following description, a process of determining whether theprobe 2 a has contacted with the sample surface is referred to as a“contact determination process.”

In addition, the determination unit 42 determines whether the probe 2 ais separated from the sample surface based on the first detection signaland the second detection signal which are output from the lightdetection unit 62. In the following description, a process ofdetermining whether the probe 2 a is separated from the sample surfaceis referred to as a “separation determination process.”

The driving control unit 43 controls an amount of relative movementbetween the probe 2 a and sample S by the movement driving unit 5. Here,the scanning probe microscope A according to the first embodiment of thepresent disclosure uses an intermittent measurement method by which thesample surface is intermittently scanned by causing the probe 2 a tocontact with the sample surface only in a plurality of preset measuringpoints. Accordingly, the driving control unit 43 controls the respectiveoperations of the approaching operation by which the probe 2 aapproaches the measuring position, the separating operation by which theprobe 2 a and the sample S are separated from each other, and a movingoperation by which the probe 2 a is moved to the position above the nextmeasuring position.

Specifically, the driving control unit 43 outputs a contact operationsignal for causing the probe 2 a and sample surface to contact with eachother to the Z-direction driving device 51 and raises the sample S.Accordingly, the driving control unit 43 causes the probe 2 a and samplesurface to contact with each other.

In a case where it is determined that the probe 2 a has contacted withthe sample surface in the contact determination process, the drivingcontrol unit 43 stops the approaching operation of raising the sample Sby stopping the output of the contact operation signal to theZ-direction driving device 51.

The driving control unit 43 outputs the separating operation signal forseparating the sample surface from the probe 2 a, to the Z-directiondriving device 51, and lowers the sample S. Accordingly, the drivingcontrol unit 43 causes the sample surface to be moved in a directionbeing separated from the probe 2 a. That is, the driving control unit 43causes the sample surface to be retracted from a state of contactingwith the probe 2 a.

Here, one of the features of the first embodiment is that, in theseparating operation, the driving control unit 43 moves the sample S inthe direction of being separated from the probe 2 a at a speed exceedinga response speed of the cantilever 2. The response speed is an averagemovement speed that is calculated based on a resonant frequency of thecantilever 2 and amplitude with which a stable operation is possible atthe resonant frequency. Thus, the separating operation according to thefirst embodiment is an operation in which the sample S is operated inthe direction of being separated from the probe 2 a at the speedexceeding the response speed of the cantilever 2.

In a case where it is determined that the probe 2 a is separated fromthe sample surface in the separation determination process, the drivingcontrol unit 43 stops the separating operation of lowering the sample Sby stopping the output of the separating operation signal to theZ-direction driving device 51.

The driving control unit 43 moves the probe 2 a to a before-loweringmeasurement position that is located immediately above the nextmeasurement position by outputting a driving signal to the XY scanner52.

The measurement unit 44 measures an uneven shape of the sample surfacein a state where the probe 2 a and the sample surface contact with eachother. For elevation stage, in a case where it is determined that theprobe 2 a has contacted with the sample surface in the contactdetermination process, the measurement unit 44 measures the uneven shapeof the sample surface by measuring a distance of relative movement ofthe sample surface with respect to the probe 2 a in the approachingoperation (hereinafter, simply referred to as “relative distance”). Forexample, the measurement unit 44 may calculate the relative distancebased on a voltage value of the driving signal in a state where theprobe 2 a and the sample surface contact with each other. In addition,the measurement unit 44 may directly measure the displacement of thesample stage 4 using a sensor (not illustrated) and may also directlymeasure a height of the sample stage 4 using a sensor (not illustrated).

Next, a flow of the intermittent measurement method of the scanningprobe microscope A according to the first embodiment will be describedwith reference to FIG. 3. As an initial state, a case where the probe 2a is located in the before-lowering measurement position at apredetermined measuring point is assumed.

The driving control unit 43 starts the approaching operation of causingthe probe 2 a to approach the sample surface by outputting the contactoperation signal to the Z-direction driving device 51 and raising thesample stage 4 (Step S101).

In a case where the approaching operation is started, the determinationunit 42 executes the contact determination process of determiningwhether the probe 2 a has contacted with the sample surface, based onthe first detection signal and the second detection signal which areoutput from the light detection unit 62 (Step S102).

In a case where it is determined that the probe 2 a has contacted withthe sample surface in the contact determination process, thedetermination unit 42 stops the approaching operation (Step S103). Inthis case, since the probe 2 a is in contact with the sample surface, acertain amount of twist or deflection occurs in the cantilever.

In a case where it is determined that the probe 2 a and the samplesurface have contacted with each other, the measurement unit 44 measuresthe uneven shape of the sample surface by measuring the relativedistance (Step S104).

In a case where the measurement unit 44 has completed the measurement ofthe relative distance, the driving control unit 43 starts the separatingoperation in which the sample S is moved in the direction of beingseparated from the probe 2 a at the speed exceeding the response speedof the cantilever 2 (Step S105).

In a case where the separating operation is started, the determinationunit 42 executes the separation determination process of determiningwhether the probe 2 a is separated from the sample surface, based on thefirst detection signal and the second detection signal which are outputfrom the light detection unit 62 (Step S106).

In a case where it is determined that the probe 2 a is separated fromthe sample surface in the separation determination process, the drivingcontrol unit 43 stops the separating operation (Step S107). The drivingcontrol unit 43 outputs the driving signal to the XY scanner 52, therebymoving the probe 2 a to the before-lowering measurement position that islocated immediately above the next measurement position (Step S108). Thedriving control unit 43 lowers the cantilever 2 from the before-loweringmeasurement position and brings the probe 2 a into contact with thesample surface in the next measurement position, then, the measurementunit 44 starts the measurement of the relative distance again. In thismanner, the scanning probe microscope A performs operations from StepsS101 to S108 corresponding to respective measuring points of the samplesurface to scan the sample surface intermittently.

Hereinafter, the contact determination process according to the firstembodiment will be described.

In a case where the deflection amount indicated by the first detectionsignal output from the light detection unit 62 exceeds a first range,the determination unit 42 determines that the probe 2 a has contactedwith the sample surface.

In a case where the twist amount indicated by the second detectionsignal output from the light detection unit 62 exceeds a second range,the determination unit 42 determines that the probe 2 a has contactedwith the sample surface.

In this manner, in a case where at least one of a first condition inwhich the deflection amount, that the first detection signal output fromthe light detection unit 62 shows, exceeds the first range and a secondcondition in which the twist amount, that the second detection signaloutput from the light detection unit 62 shows, exceeds the second range,is established, the determination unit 42 determines that the probe 2 ahas contacted with the sample surface. In the above, although a casewhere the first detection signal and the second detection signal areindependently determined is exemplified, a determination may beperformed based on a set value corresponding to the characteristics, forexample, in the determination unit 42, it may be determined to a contactstate in a case where a “square of the first detection signal” and a“square of the second detection signal” are added together and apositive number of the square root of the sum is equal to or greaterthan a certain value.

Hereinafter, the first range and the second range in the presentembodiment will be described with reference to FIG. 4. As shown in FIG.4, the first range is a range between a deflection upper limit thresholdand a deflection lower limit threshold. The deflection upper limit isthe deflection amount of the cantilever 2 that is deflected in the +Zdirection by contact between surfaces of the probe 2 a and the sample S.Meanwhile, the deflection lower limit is the deflection amount of thecantilever 2 that is deflected in the −Z direction by contact betweensurfaces of the probe 2 a and the sample S. Accordingly, in a case wherethe deflection amount, that the first detection signal output from thelight detection unit 62 shows, exceeds the deflection upper limit or ina case where the deflection amount, that the first detection signalshows, falls below the deflection lower limit, the determination unit 42determines that the probe 2 a has contacted with the sample surface.

The second range is a range between a twist upper limit threshold and atwist lower limit threshold. The twist upper limit is the twist amountof the cantilever 2 that is twisted in the +Y direction by contactbetween surfaces of the probe 2 a and the sample S. Meanwhile, the twistlower limit is the twist amount of the cantilever 2 that is twisted inthe −Y direction by contact between the probe 2 a and the samplesurface. Accordingly, in a case where the twist amount, that the seconddetection signal output from the light detection unit 62 shows, exceedsthe twist upper limit or in a case where the twist amount, that thesecond detection signal shows, falls below the twist lower limit, thedetermination unit 42 determines that the probe 2 a has contacted withthe sample surface. In this manner, in a case where a position, that thedeflection amount shown by the first detection signal and the twistamount shown by the second detection signal show, is positioned outsidea shaded area in a two-dimensional coordinate of the deflection amountand the twist amount shown in FIG. 4, it is determined that the probe 2a has contacted with the sample surface.

Next, the separation determination process according to the firstembodiment will be described.

In a case where a vibration of the cantilever 2 with predeterminedamplitude is detected at the resonant frequency of the cantilever in theseparating operation, the discharge passage 42 determines that the probe2 a is separated from the sample surface. The predetermined amplitude isa range smaller than the displacement of the cantilever 2 in a statewhere the probe 2 a is in contact with the sample surface, withreference to an amplitude of the cantilever 2 due to thermal vibrationin the free state.

For example, the separation determination process is a process ofdetermining whether a rate of change in the amplitude in the deflectiondirection in the vicinity of the resonant frequency of the cantilever 2is equal to or greater than a predetermined value, in a case where thesample S is operated in the separating direction from the probe 2 a atthe speed exceeding the response speed of the cantilever 2. Here, thecase where the rate of change in the amplitude in the deflectiondirection represents a case where the amplitude in the deflectiondirection rapidly increases. The separation determination process may bea process of determining whether the frequency of the vibration of thecantilever 2 with predetermined amplitude is the resonant frequency ofthe cantilever, in a case where the sample S is operated in theseparating direction from the probe 2 a at the speed exceeding theresponse speed of the cantilever 2.

In a case where the sample S is operated in the separating directionfrom the probe 2 a at the speed exceeding the response speed of thecantilever 2, when it is determined that a vibration frequency of thecantilever 2 is the resonant frequency of the cantilever and the rate ofchange in the amplitude of the cantilever 2 is equal to or greater thanthe predetermined value, the determination unit 42 determines that theprobe 2 a is separated from the sample surface. On the other hand, in acase where the sample S is operated in the separating direction from theprobe 2 a at the speed exceeding the response speed of the cantilever 2,when it is determined that the vibration frequency of the cantilever 2is not the resonant frequency of the cantilever or the rate of change inthe amplitude of the cantilever 2 is less than the predetermined value,the determination unit 42 determines that the probe 2 a and the samplesurface contact with each other (are not separated from each other).

Hereinafter, an operation effect of the separation determination processaccording to the first embodiment will be described with reference toFIGS. 5A, 5B, 6A, and 6B.

FIGS. 5A and 5B are diagrams showing a state of the cantilever 2 in acase where the sample S is moved in a direction being separated from theprobe 2 a at a normal speed. FIGS. 6A and 6B are diagrams showing astate of the cantilever 2 in a separating operation (in a case where thesample S is operated in the direction being separated from the probe 2 aat a speed exceeding a response speed of the cantilever 2) according tothe first embodiment. FIGS. 5A and 6A show side views of the cantilever2 as viewed from the −Y direction, and FIGS. 5B and 6B show side viewsof the cantilever 2 as viewed from −X direction.

In a case where at least one of the deflection amount and the twistamount of the cantilever 2 is out of a predetermined range in the abovedescribed contact determination process, the determination unit 42determines that the probe 2 a has contacted with the sample surface.Accordingly, in contraposition with above, if the deflection amount andthe twist amount of the cantilever 2 are within the predeterminedranges, the probe 2 a is not in contact with the sample surface, thatis, it represents that the probe 2 a and the sample surface areseparated from each other.

However, there may be adsorption power between the probe 2 a and thesample surface in some cases. Therefore, as shown in FIGS. 5A and 5B, ina case where the sample S is separated from the probe 2 a at a normalspeed, even in a case where the deflection amount and the twist amountof the cantilever 2 are within the predetermined range, the probe 2 aand the sample surface may be in contact with each other by theadsorption power. In addition, the adsorption power between the probe 2a and the sample surface may be different at each measuring point.Accordingly, it is not possible to uniquely set the respectivethresholds of the deflection amount and the twist amount when the probe2 a and the sample surface are separated from each other.

On the other hand, as shown in FIGS. 6A and 6B, in the first embodiment,the driving control unit 43 separates the sample S from the probe 2 a atthe speed exceeding the response speed of the cantilever 2. Here, theprobe 2 a cannot move faster than the response speed of the cantilever2. Accordingly, when the sample S is separated from the probe 2 a at thespeed exceeding the response speed of the cantilever 2, even in a casewhere there is the adsorption power between the probe 2 a and the samplesurface, the probe 2 a is immediately separated from a state ofcontacting with the sample surface.

Accordingly, the cantilever 2 resonates with the amplitude from a statein which the probe 2 a and the sample surface contact with each other,that is, a state in which the probe 2 a is pushed upward, to the freestate. In other words, the amplitude in the deflection direction at theresonant frequency of the cantilever 2 rapidly increases. Therefore, ina case where the vibration of the cantilever 2 with the amplitude in thedeflection direction is detected at the resonant frequency (includinghigh-order frequency) of the cantilever 2 during the separatingoperation, the determination unit 42 according to the first embodimentdetermines that the probe 2 a is separated from the sample surface.Accordingly, even in a case where there is the adsorption power betweenthe probe 2 a and the sample surface, it is possible to certainly detectthat the probe 2 a is separated from the sample surface.

In a case where the separation is performed at the speed exceeding theresponse speed of the cantilever 2, when there is no adsorption powerbetween the probe 2 a and the sample surface, the vibration startingfrom the deflected state of the cantilever 2 occurs at the resonantfrequency in the deflection direction.

Hereinafter, a flow of the separation determination process according tothe first embodiment will be described with reference to FIG. 7.

The determination unit 42 determines whether the deflection amountindicated by the first detection signal output from the light detectionunit 62 is within the first range (Step S201). In a case where the it isdetermined that the deflection amount, that the first detection signaloutput from the light detection unit 62 shows, is within the firstrange, the determination unit 42 determines whether the twist amount,that the second detection signal output from the light detection unit 62shows, is within the second range (Step S202). On the other hand, in acase where the deflection amount, that the first detection signal outputfrom the light detection unit 62 shows, is out of the first range, thedetermination unit 42 determines that the probe 2 a is not separatedfrom the sample surface (Step S206).

In a case where it is determined that the twist amount, that the seconddetection signal output from the light detection unit 62 shows, iswithin the second range, the determination unit 42 determines whetherthe frequency of the first detection signal is the resonant frequency ofthe cantilever 2 (Step S203). On the other hand, in a case where it isdetermined that the twist amount, that the second detection signaloutput from the light detection unit 62 shows, is out of the secondrange, the determination unit 42 determines that the probe 2 a is notseparated from the sample surface (Step S206).

In a case where it is determined that the frequency of the firstdetection signal is the resonant frequency of the cantilever 2, thedetermination unit 42 determines whether the rate of change in thedeflection amount, that the first signal shows, exceeds a predeterminedvalue (Step S204). Meanwhile, in a case where it is determined that thefrequency of the first detection signal is not the resonant frequency ofthe cantilever 2, the determination unit 42 determines that the probe 2a is not separated from the sample surface (Step S206).

In a case where the change in deflection amount, that the firstdetection signal shows, exceeds a predetermined value, the determinationunit 42 determines that the probe 2 a is separated from the samplesurface (Step S205). Meanwhile, in a case where the change in deflectionamount, that the first detection signal shows, exceeds a predeterminedvalue, the determination unit 42 determines that the probe 2 a is notseparated from the sample surface (Step S206).

In FIG. 7, the process of Step S202 is executed after the process ofStep S201; however, it is not limited thereto. The determination unit 42of the present embodiment may perform the process of Step S201 after theprocess of Step S202 and may execute the process of Step S201 and theprocess of S202 in parallel. In the same manner, the determination unit42 may execute the process of Step S204 after the process of Step S203,and may execute the process of Step S203 and the process of S204 inparallel.

As described above, in a case where the vibration of the cantilever 2 atthe predetermined amplitude is detected at the resonant frequency(including high-order frequency) of the cantilever 2 during theseparating operation in which the sample S is separated from the probe 2a at the speed exceeding the response speed of the cantilever 2, thescanning probe microscope A according to the first embodiment determinesthat the probe 2 a is separated from the sample surface. The scanningprobe microscope A stops the separating operation by the Z-directiondriving device 51 at a moment of time when it is determined that theprobe 2 a is separated from the sample surface and relatively moves theprobe 2 a and the sample to a position where the probe 2 a is locatedimmediately above the next measuring point of the sample S.

Accordingly, since the scanning probe microscope A is operated at anoptimal separation distance at the respective measuring points of thesample S, it is possible to achieve the measurement of the uneven shapein the sample surface in the shortest time. Therefore, the scanningprobe microscope A is possible to improve the efficiency of measuringthe uneven shape in the sample surface.

Here, the first detection signal showing the deflection amount may driftdue to a temperature change or the like in some cases. In the relatedart, it is necessary to determine the separation distance inconsideration of the influence of this drift, and an optimization cannotbe performed in advance in some cases.

On the other hand, even in a case where the first detection signal hasdrifted, the scanning probe microscope A according to the firstembodiment successively determines whether the probe 2 a is separatedfrom the sample surface. According to this, the scanning probemicroscope A is not affected by the drift and can be operated at theoptimal separation distance.

In the above described embodiment, the Z-direction driving device 51 isnecessary to perform the separating operation in which the sample S ismoved in the direction being separated from the probe 2 a at a speed atwhich the vibration does not occur. According to this, the Z-directiondriving device 51 may have a configuration using a laminatedpiezoelectric element 510. For example, as shown in FIG. 8, theZ-direction driving device 51 includes the laminated piezoelectricelement 510, flat springs 511 and 512 that have the same springconstant, support-plates 521 and 522 that respectively fix the flatsprings 511 and 512, and a base 530.

In one end of the laminated piezoelectric element 510, the sample stage4 and the sample S are provided via the flat spring 511. In addition, inthe other end of the laminated piezoelectric element 510, the base 530is provided via the flat spring 512. The weight of the base 530corresponds to the weight of the sample stage 4 and sample S.

In a case where the Z-direction driving device 51 is fixed, theZ-direction driving device 51 is fixed at the center of each of thesupport plates 521 and 522. Accordingly, the Z-direction driving device51 can prevent the vibration from being transmitted to the surroundingseven when performing the separating operation.

Second Embodiment

Hereinafter, a scanning probe microscope B according to a secondembodiment will be described with reference to the drawings. Thescanning probe microscope B according to the second embodiment performsa separation determination process based on the speed change of thecantilever 2 in the deflection direction, unlike the “separationdetermination process” according to the first embodiment. As a “contactdetermination process”, the scanning probe microscope B according to thesecond embodiment performs the same process as the “contactdetermination process” according to the first embodiment.

FIG. 9 is a diagram showing an example of a schematic configuration ofthe scanning probe microscope B according to the second embodiment. Asshown in FIG. 9, the scanning probe microscope B includes a cantilever2, a sample stage 4, a movement driving unit 5, a displacement detectingunit 6, and a control device 7B.

The control device 7B includes a determination unit 42B, a drivingcontrol unit 43B, and a measurement unit 44.

The determination unit 42B performs the contact determination process ofdetermining whether the probe 2 a has contacted with the sample surface,based on the first detection signal and the second detection signalwhich are output from the light detection unit 62. The contactdetermination process of the determination unit 42B is the same as thecontact determination process according to the first embodiment.

In addition, the determination unit 42B performs the separationdetermination process of determining whether the probe 2 a is separatedfrom the sample surface, based on the first detection signal and thesecond detection signal which are output from the light detection unit62. Specifically, the separation determination process of thedetermination unit 42B is to determine the separation of the probe 2 awith respect to the sample surface, based on the speed change of thecantilever 2 in the deflection direction during the separatingoperation.

The driving control unit 43B causes the sample S to be moved in thedirection of being separated from the probe 2 a at a speed equal to orlower than the response speed of the cantilever 2. That is, regardingthe separating operation, in the first embodiment, the sample S isoperated in the direction of being separated from the probe 2 a at thespeed exceeding the response speed of the cantilever 2, whereas in thesecond embodiment, the sample S is moved in the direction of beingseparated from the probe 2 a at the speed equal to or lower than theresponse speed of the cantilever 2. The operations relating to thedriving control unit 43B other than the separating operation are thesame as those of the driving control unit 43.

Hereinafter, the separation determination process according to thesecond embodiment will be described.

The determination unit 42B determines the separation of the probe 2 awith respect to the sample surface, based on the speed change of thecantilever 2 in the deflection direction during the separating operationin which the sample S is separated from the probe 2 a at the speed equalto or lower than the response speed of the cantilever 2.

Here, the determination unit 42B can calculate the speed change of thecantilever 2 in the deflection direction from a ratio (Vd/H) between adeflection amount Vd of the cantilever 2 and a separated distance H ofthe sample S from the probe 2 a. In addition, the determination unit 42Bcan calculate the speed change of the cantilever 2 in the deflectiondirection by differentiating the deflection amount Vd of the cantilever2.

In a case where the speed of the cantilever 2 in the deflectiondirection is equal to or lower than a predetermined value during theseparating operation in which the sample S is separated from the probe 2a at the speed equal to or lower than the response speed of thecantilever 2, the determination unit 42B determines that the probe 2 ais separated from the sample surface.

In addition, in a case where a speed direction of the cantilever 2 isreversed during the separating operation in which the sample S isseparated from the probe 2 a at the speed equal to or lower than theresponse speed of the cantilever 2, the determination unit 42Bdetermines that the probe 2 a is separated from the sample surface.

Hereinafter, an operation effect of the separation determination processaccording to the second embodiment will be described with reference tothe drawings.

FIGS. 10A and 10B are graphs showing the speed change of the cantilever2 in the deflection direction, in the separating operation according tothe second embodiment. FIG. 10A is a graph of the speed change of thecantilever 2 in the deflection direction in a case where there is noadsorption power between the probe 2 a and the sample S. FIG. 10B is agraph of the speed change of the cantilever 2 in the deflectiondirection in a case where there is the adsorption power between theprobe 2 a and the sample S. FIGS. 11A and 11B are diagrams showing astate of the cantilever 2 in the separating operation (in a case wherethe sample S is operated in the direction being separated from the probe2 a at a speed equal to or lower than the response speed of thecantilever 2) according to the second embodiment. FIG. 11A shows a sideview of the cantilever 2 as viewed from the −Y direction, and FIG. 11Bshows a side view of the cantilever 2 as viewed from −X direction.

In a case where the probe 2 a and the sample surface are in contact witheach other during the separating operation, a speed of the solutiontreatment in the deflection direction becomes a constant value.

Here, as shown in FIG. 10A, in a case where there is no adsorption powerbetween the probe 2 a and the sample S, when the probe 2 a and thesample surface are separated from each other, the change in thedeflection amount of the cantilever 2, that is, the speed of thecantilever 2 becomes appropriately zero in the free state. Therefore, ina case where the speed of the cantilever 2 in the deflection directionis equal to or lower than a predetermined value during the separatingoperation in which the sample S is separated from the probe 2 a at thespeed equal to or lower than the response speed of the cantilever 2, thedetermination unit 42B determines that the probe 2 a is separated fromthe sample surface. Accordingly, in a case where there is no theadsorption power between the probe 2 a and the sample S, thedetermination unit 42B can certainly detect the separation between theprobe 2 a and the sample S. In a case where the probe 2 a and the samplesurface are in contact with each other, the predetermined value is avalue lower than the speed of the cantilever 2 in the deflectiondirection.

Meanwhile, as shown in FIGS. 10B, 11A, and 11B, in a case where there isthe adsorption power between the probe 2 a and the sample S, since thedeflection parts due to the adsorption power returns when the probe 2 ais separated from the sample surface, a sign of the value of Vd/H isreversed. That is, when the probe 2 a and the sample surface areseparated from each other, the speed direction of the cantilever 2 isreversed. Therefore, in a case where the speed direction of thecantilever 2 is reversed during the separating operation, thedetermination unit 42B determines that the probe 2 a is separated fromthe sample surface. Accordingly, even in a case where there is theadsorption power between the probe 2 a and the sample S, thedetermination unit 42B can certainly detect the separation between theprobe 2 a and the sample S.

Hereinafter, a flow of the separation determination process according tothe second embodiment will be described with reference to FIG. 12.

The determination unit 42B determines whether the deflection amountindicated by the first detection signal output from the light detectionunit 62 is within the first range (Step 301). In a case where the it isdetermined that the deflection amount, that the first detection signaloutput from the light detection unit 62 shows, is within the firstrange, the determination unit 42B determines whether the twist amount,that the second detection signal output from the light detection unit 62shows, is within the second range (Step S302). On the other hand, in acase where the deflection amount, that the first detection signal outputfrom the light detection unit 62 shows, is out of the first range, thedetermination unit 42B determines that the probe 2 a is not separatedfrom the sample surface (Step S306).

In a case where it is determined that the twist amount, that the seconddetection signal output from the light detection unit 62 shows, iswithin the second range, the determination unit 42B determines whetherthe speed of the cantilever 2 calculated based on the first detectionsignal is equal to or lower than a predetermined value (Step S303). Onthe other hand, in a case where it is determined that the twist amount,that the second detection signal output from the light detection unit 62shows, is out of the second range, the determination unit 42B determinesthat the probe 2 a is not separated from the sample surface (Step S306).

In a case where it is determined that the speed of the cantilever 2 isequal to or lower than a predetermined value, the determination unit 42Bdetermines that the probe 2 a is separated from the sample surface (StepS305). Meanwhile, in a case where it is determined that the speed of thecantilever 2 exceeds a predetermined value, the determination unit 42Bdetermines whether the speed direction of the cantilever 2 is reversed(Step S304).

In a case where it is determined that the speed direction of thecantilever 2 is reversed, the determination unit 42B determines that theprobe 2 a is separated from the sample surface (Step S305). Meanwhile,in a case where it is determined that the speed direction of thecantilever 2 is not reversed, the determination unit 42B determines thatthe probe 2 a is not separated from the sample surface (Step S306).

In FIG. 12, the process of Step S302 is executed after the process ofStep S301; however, it is not limited thereto. The determination unit42B of the present embodiment may perform the process of Step S301 afterthe process of Step S302 and may execute the process of Step S301 andthe process of S302 in parallel. In the same manner, the determinationunit 42B may execute the process of Step S304 after the process of StepS303, and may execute the process of Step S303 and the process of S304in parallel.

As described above, the scanning probe microscope B according to thesecond embodiment determines the separation of the probe 2 a withrespect to the sample surface, based on the speed change of thecantilever 2 in the deflection direction during the separating operationin which the sample S is separated from the probe 2 a at the speed notexceeding the response speed of the cantilever 2.

For example, in a case where the speed of the cantilever 2 in thedeflection direction reaches a value equal to or lower than apredetermined value, the determination unit 42B determines that theprobe 2 a is separated from the sample surface. In addition, in a casewhere the probe 2 a is reversed in the speed direction, thedetermination unit 42B determines that the probe 2 a is separated fromthe sample surface.

Accordingly, since the scanning probe microscope B is operated at theoptimal separation distance at the respective measuring points of thesample S even in a case where there is the adsorption power between theprobe 2 a and sample S, it is possible to achieve the measurement of theuneven shape in the sample surface in the shortest time. Therefore, thescanning probe microscope B is possible to improve the efficiency ofmeasuring the uneven shape in the sample surface.

In the second embodiment, in the separating operation, the sample andthe probe 2 a are separated from each other by lowering the sample S;however, it is not limited thereto. The driving control unit 43B mayseparate the sample S and the probe 2 a from each other by raising theprobe 2 a.

Third Embodiment

Hereinafter, a scanning probe microscope C according to a thirdembodiment will be described with reference to the drawings. Thescanning probe microscope C according to the third embodiment performs aseparation determination process based on an increase of the amplitudeof the vibration in the cantilever 2 or a change of the vibrationfrequency of the vibration, unlike the “separation determinationprocess” according to the first embodiment. As a “contact determinationprocess”, the scanning probe microscope C according to the thirdembodiment performs the same process as the “contact determinationprocess” according to the first embodiment.

FIG. 13 is a diagram showing an example of a schematic configuration ofthe scanning probe microscope C according to the third embodiment. Asshown in FIG. 13, the scanning probe microscope C includes a cantilever2, a sample stage 4, a movement driving unit 5, a displacement detectingunit 6, and a control device 7C.

The control device 7C includes a determination unit 42C, the drivingcontrol unit 43B, and a measurement unit 44.

The determination unit 42C performs the contact determination process ofdetermining whether the probe 2 a has contacted with the sample surface,based on the first detection signal and the second detection signalwhich are output from the light detection unit 62. The contactdetermination process of the determination unit 42C is the same as thecontact determination process according to the first embodiment.

The determination unit 42C performs the separation determination processof determining whether the probe 2 a is separated from the samplesurface, based on the first detection signal and the second detectionsignal which are output from the light detection unit 62.

Hereinafter, a separation determination process according to the thirdembodiment will be described with reference FIGS. 14A and 14B.

For the separation determination process according to the thirdembodiment, there are roughly two methods of “a method of detecting achange of the amplitude of the deflection or the twist due to thermalvibration of the cantilever” and “detecting a change of the resonantfrequency of the deflection or the twist due to thermal vibration of thecantilever.”

<Method of Detecting Change in Amplitude of Deflection or Twist Due toThermal Vibration or Cantilever>

In the cantilever 2, the base end is fixed and the tip (the probe 2 a)is configured as a free end. Therefore, in a case where the probe 2 a isnot in contact with the sample surface, that is, is in a separatedstate, the cantilever 2 resonates with large amplitude due to a thermalvibration. In the following, a state of the cantilever 2 of which thebase end is a fixed end and the tip (probe 2 a) is the free end isreferred to as a cantilever state.

On the other hand, in a case where the probe 2 a is in contact with thesample surface, the probe 2 a becomes to be fixed by the sample surface.That is, both the base end and the tip of the cantilever 2 become thefixed end. Therefore, the amplitude of the resonance due to the thermalvibration becomes smaller amplitude as compared to the cantilever state.Hereinafter, the state of the cantilever 2 of which both the base endand the tip are the fixed end is referred to as a doubly-supportedstate.

In a case of moving from a state where the probe 2 a is in contact withthe sample surface is shifted to a state where the probe 2 a isseparated from the sample surface, the amplitude of the vibration of thecantilever 2 becomes to increase. Then, the determination unit 42Cdetermines the separation of the probe 2 a with respect to the samplesurface, based on the increase of the amplitude in the vibration of thecantilever 2. For example, in a case where the amplitude of thevibration in the cantilever 2 reaches a value equal to or larger than apredetermined value during the separating operation, the determinationunit 42C determines that the probe 2 a and the sample surface have beenseparated from each other. The amplitude of the vibration in thecantilever 2 is at least one of deflection amplitude and twistamplitude. In addition, the predetermined value is set based on theamplitude of the vibration of the cantilever 2 in the doubly-supportedstate.

<Detecting Change of Resonant Frequency of Deflection or Twist Due toCantilever>

The resonant frequency of the cantilever 2 resonating due to the thermalvibration is different in the cantilever state and the doubly-supportedstate. Therefore, the state where the probe 2 a is in contact with thesample surface is shifted to the state where the probe 2 a is separatedfrom the sample surface, the resonant frequency of the cantilever 2changes. Hereinafter, the resonant frequency of the cantilever 2 in thecantilever state is referred to as a cantilever resonant frequency.Meanwhile, the resonant frequency of the cantilever 2 in thedoubly-supported state is referred to as a doubly-supported-beamresonant frequency.

The determination unit 42C determines the separation of the probe 2 awith respect to the sample surface, based on the change in the resonantfrequency of the vibration in the cantilever 2 during the separatingoperation. For example, in a case where the change in the vibrationfrequency of the cantilever 2 during the separating operation reaches avalue equal to or greater than a predetermined value, the determinationunit 42C determines that the probe 2 a and the sample surface have beenseparated from each other. The vibration in the cantilever 2 is afrequency of the vibration in at least one direction of the deflectiondirection and the twist direction. In addition, the predetermined valueis set based on the doubly-supported-beam resonant frequency.

In any of the two separation determination processes described above,for determining the separation of the probe 2 a with respect to thesample surface, it is a condition that the deflection amount, that thefirst signal output from the light detection unit 62 shows, is withinthe first range, and the twist amount, that the second signal outputfrom the light detection unit 62 shows, is within the second range.

As described above, the scanning probe microscope C according to thethird embodiment determines the separation of the probe 2 a with respectto the sample surface, based on the increase of the vibration in thecantilever 2 or the change of the vibration frequency of the vibrationduring the separating operation. Accordingly, since the scanning probemicroscope C is operated at the optimal separation distance at therespective measuring points of the sample S even in a case where thereis the adsorption power between the probe 2 a and sample S, it ispossible to achieve the measurement of the uneven shape in the samplesurface in the shortest time. Therefore, the scanning probe microscope Cis possible to improve the efficiency of measuring the uneven shape inthe sample surface.

In addition, since the scanning probe microscope C detects theseparation between the probe 2 a and the sample surface, there is noneed to newly provide a structure.

Fourth Embodiment

Hereinafter, a scanning probe microscope D according to a fourthembodiment will be described with reference to the drawings. Thescanning probe microscope D according to the fourth embodiment includesan oscillation unit 3 and performs a separation determination processbased on a change in amplitude of a predetermined frequency in adeflection direction or a twist direction of the cantilever 2, unlikethe “separation determination process” according to the firstembodiment. As a “contact determination process”, the scanning probemicroscope D according to the fourth embodiment performs the sameprocess as the “contact determination process” according to the firstembodiment.

FIG. 15 is a diagram showing an example of a schematic configuration ofthe scanning probe microscope D according to the fourth embodiment. Asshown in FIG. 15, the scanning probe microscope D includes a cantilever2, an oscillation unit 3, a sample stage 4, a movement driving unit 5, adisplacement detecting unit 6, and a control device 7D.

The oscillation unit 3 relatively vibrates the sample S and thecantilever 2 at a predetermined frequency in a separating operation. Forexample, the oscillation unit 3 may excite the cantilever 2, or mayexcite the sample stage 4. In addition, a direction of the relativevibration between the sample S and the cantilever 2 at a predeterminedfrequency may be a direction (Z-direction) perpendicular to thehorizontal plane or a horizontal direction (Y-direction) of the samplestage 4. In the following description, the predetermined frequency isreferred to as an oscillation frequency.

The control device 7D includes a determination unit 42D, a drivingcontrol unit 43D, and a measurement unit 44.

The determination unit 42D performs a separation determination processof determining whether a probe 2 a is separated from a sample surface,based on a first detection signal and a second detection signal whichare output from a light detection unit 62. Specifically, the separationdetermination process of the determination unit 42D is to determine theseparation of the probe 2 a with respect to the sample surface, based onthe change in amplitude of the oscillation frequency in the deflectiondirection or the twist direction of the cantilever 2.

The driving control unit 43D has the same function as that of thedriving control unit 43B. Further, the driving control unit 43D controlsthe operation of the oscillation unit 3. That is, the driving controlunit 43D controls relative vibration between the sample S and thecantilever 2.

Hereinafter, the separation determination process according to thefourth embodiment will be described with reference FIGS. 16A, 16B, 17A,17B, 18A, and 18B.

For the separation determination process according to the fourthembodiment, there are roughly three methods of “a method of detecting adecrease amount of an amplitude in a non-resonant frequency in thedeflection direction or the twist direction of the cantilever”, “amethod of detecting an increase amount of an amplitude in a resonantfrequency in the deflection direction or the twist direction of thecantilever”, and ““a method of detecting a decrease amount of anamplitude in the resonant frequency in the deflection direction or thetwist direction of the cantilever.”

<Method of Detecting Decrease Amount of Amplitude at Non-ResonantFrequency in Deflection Direction or Twist Direction of Cantilever:FIGS. 16A and 16B>

In this method, the oscillation frequency is set to a non-resonantfrequency of the cantilever 2. Then, the oscillation unit 3 slightlyvibrates the sample S relative to the cantilever 2 at a non-resonantfrequency in the separating operation. In this case, when the probe 2 ais in contact with the surface of the sample, the angle of thecantilever 2 changes with the probe 2 a as a fulcrum. That is, the anglechange of the cantilever 2 is detected as large amplitude of thecantilever 2 in a detection method using an optical lever type.

On the other hand, when the probe 2 a and the surface of the sample areseparated from each other in the separating operation, since the probe 2a is away from the surface of the sample, the angle change of thecantilever 2 decreases. For this reason, the angle change of thecantilever is detected as small amplitude of the cantilever 2 in thedetection method using the optical lever type. Therefore, in a case ofmoving from state where the probe 2 a is in contact with the surface ofthe sample to the state where the probe 2 a is separated from thesurface of the sample, the amplitude of the cantilever 2 decreases.Here, the amplitude of the cantilever 2 is at least one of the amplitudein the deflection direction and the amplitude in the twist direction.The amplitude in the deflection direction is a deflection amountindicated by the first detection signal. The amplitude in the twistdirection is a twist amount indicated by the second detection signal.

Therefore, the determination unit 42D determines that the probe 2 a isseparated from the surface of the sample when the decrease amount of theamplitude at the non-resonant frequency in the deflection direction orthe twist direction of the cantilever 2 exceeds a predetermined value inthe separating operation. In addition, the predetermined value is setbased on the deflection amount or the twist amount detected in a statewhere the probe 2 a is in contact with the surface of the sample in theseparating operation.

In this method, it may slightly vibrate the cantilever 2 at thenon-resonant frequency in the deflection direction, or may vibrate thecantilever 2 in the horizontal direction. In the fourth embodiment, itmay slightly vibrate the sample S at the non-resonant frequency in thedeflection direction, or may vibrate the sample S in the horizontaldirection.

<Method of Detecting Increase Amount of Amplitude at Resonant Frequencyin Deflection Direction or Twist Direction of Cantilever; FIGS. 17A and17B>

In this method, the oscillation frequency is set to a cantileverresonant frequency. Then, the oscillation unit 3 slightly vibrates thesample S relative to the cantilever 2 at a cantilever resonant frequencyin the separating operation. In this case, the cantilever 2 is in adoubly-supported state when the probe 2 a is in contact with the surfaceof the sample. For this reason, even if being excited at the cantileverresonant frequency by the oscillation unit 3, the cantilever 2 does notresonate and vibrates with small amplitude.

On the other hand, when the probe 2 a and the surface of the sample areseparated from each other in the separating operation, since the probe 2a is away from the surface of the sample, the cantilever 2 is in acantilever state. Therefore, the cantilever 2 resonates by being excitedwith the cantilever resonant frequency by the oscillation unit 3, andvibrates with large amplitude.

Therefore, in a case of moving from state where the probe 2 a is incontact with the surface of the sample to the state where the probe 2 ais separated from the surface of the sample, the amplitude of vibrationof the cantilever 2 at the cantilever resonant frequency increases.Therefore, the determination unit 42D determines the separation of theprobe 2 a from the surface of the sample based on the increase inamplitude of the vibration of the cantilever 2 at the cantileverresonant frequency in the separation operation. For example, thedetermination unit 42D determines that the probe 2 a is separated fromthe surface of the sample when the increase amount of the vibrationamplitude of the cantilever 2 at the cantilever resonant frequencyexceeds a predetermined value in the separating operation. In addition,the vibration amplitude of the cantilever 2 is at least one of thedeflection amplitude and the twist amplitude.

In this method, it may slightly vibrate the cantilever 2 at thecantilever resonant frequency in the deflection direction, or mayvibrate the cantilever 2 at the cantilever resonant frequency in thehorizontal direction. In addition, it may slightly vibrate the sample Sat the cantilever resonant frequency in the deflection direction, or mayvibrate the sample S at the cantilever resonant frequency in thehorizontal direction.

However, when the vibration slightly occurs in the deflection direction,the oscillation frequency is the cantilever resonant frequency of thecantilever 2 in the deflection direction. On the other hand, when thevibration slightly occurs in the horizontal direction, the oscillationfrequency is the cantilever resonant frequency of the cantilever 2 inthe horizontal direction.

<Method of Detecting Decrease Amount of Amplitude at Resonant Frequencyin Deflection Direction or Twist Direction of Cantilever; FIGS. 18A and18B>

In this method, the oscillation frequency is set to adoubly-supported-beam resonant frequency. Then, the oscillation unit 3slightly vibrates the sample S relative to the cantilever 2 at thedoubly-supported-beam resonant frequency in the separating operation. Inthis case, the cantilever 2 is in a doubly-supported state when theprobe 2 a is in contact with the surface of the sample. For this reason,the cantilever 2 resonates by being excited at the doubly-supported-beamresonant frequency by the oscillation unit 3, and vibrates with largeamplitude.

On the other hand, when the probe 2 a and the surface of the sample areseparated from each other in the separating operation, since the probe 2a is away from the surface of the sample, the cantilever 2 is in acantilever state. For this reason, even if being excited at thedoubly-supported-beam resonant frequency by the oscillation unit 3, thecantilever 2 does not resonate and vibrates with small amplitude.

Therefore, in a case of moving from state where the probe 2 a is incontact with the surface of the sample to the state where the probe 2 ais separated from the surface of the sample, the amplitude of vibrationof the cantilever 2 at the doubly-supported-beam resonant frequencydecreases. Therefore, the determination unit 42D determines theseparation of the probe 2 a from the surface of the sample based on thedecrease in amplitude of the vibration of the cantilever 2 atdoubly-supported-beam resonant frequency in the separation operation.For example, the determination unit 42D determines that the probe 2 a isseparated from the surface of the sample when the decrease amount of thevibration amplitude of the cantilever 2 at the doubly-supported-beamresonant frequency exceeds a predetermined value in the separatingoperation. In addition, the vibration amplitude of the cantilever 2 isat least one of the deflection amplitude and the twist amplitude.

In this method, it may slightly vibrate the cantilever 2 at thedoubly-supported-beam resonant frequency in the deflection direction, ormay vibrate the cantilever 2 at the doubly-supported-beam resonantfrequency in the horizontal direction. In addition, it may slightlyvibrate the sample S at the doubly-supported-beam resonant frequency inthe deflection direction, or may vibrate the sample S at thedoubly-supported-beam resonant frequency in the horizontal direction.

However, when the vibration slightly occurs in the deflection direction,the oscillation frequency is the doubly-supported-beam resonantfrequency of the cantilever 2 in the deflection direction. On the otherhand, when the vibration slightly occurs in the horizontal direction,the oscillation frequency is the doubly-supported-beam resonantfrequency of the cantilever 2 in the horizontal direction.

In any of the three types of separation determination processesaccording to the fourth embodiment, the separation of the probe 2 a fromthe surface of the sample is determined under conditions that thedeflection amount indicated by the first detection signal output fromthe light detection unit 62 is within a first range and the twistdirection indicated by the second detection signal output from the lightdetection unit 62 is within a second range.

As described above, the scanning probe microscope D according to thefourth embodiment includes the oscillation unit 3 that relativelyvibrates the sample S and the cantilever 2 at a predetermined frequencyin the separating operation and the determination unit 42D thatdetermines the separation of the probe 2 a from the surface of thesample based on the change in amplitude at the predetermined frequencyin the deflection direction or the twist direction of the cantilever 2during the separating operation. Accordingly, since the scanning probemicroscope D is operated at the optimal separation distance at therespective measuring points of the sample S even in a case where thereis the adsorption power between the probe 2 a and sample S, it ispossible to achieve the measurement of the uneven shape in the samplesurface in the shortest time. Therefore, the scanning probe microscope Dis possible to improve the measurement efficiency of the uneven shape inthe sample surface.

In the fourth embodiment, the method of slightly vibrating at thenon-resonate frequency in the deflection or twist direction is suitablefor the case where the amplitude sharply decreases at the moment theprobe 2 a separates from the surface of the sample, the response isfast, and the operation is performed at a high speed.

On the other hand, the method of adding minute amplitude to the resonantfrequency (cantilever resonant frequency, doubly-supported-beam resonantfrequency) makes it possible to detect with the amplitude smaller thanthe non-resonant frequency, so it has little influence on themeasurement of the uneven shape.

Fifth Embodiment

Hereinafter, the scanning probe microscope E according to a fifthembodiment will be described with reference to the drawings. Thescanning probe microscope E according to the fifth embodiment includesan oscillation unit 3 as in the fourth embodiment and performs aseparation determination process based on a phase difference between aphase of vibration in a deflection direction or a twist direction of thecantilever 2 and a phase of a resonant frequency excited by theoscillation unit 3, unlike the “separation determination process”according to the first embodiment. As a “contact determination process”,the scanning probe microscope E according to the fifth embodimentperforms the same process as the “contact determination process”according to the first embodiment.

FIG. 19 is a diagram showing an example of a schematic configuration ofthe scanning probe microscope E according to the fifth embodiment. Asshown in FIG. 19, the scanning probe microscope E includes a cantilever2, an oscillation unit 3, a sample stage 4, a movement driving unit 5, adisplacement detecting unit 6, and a control device 7E.

The control device 7E includes a determination unit 42E, a drivingcontrol unit 43D, and a measurement unit 44.

The determination unit 42E performs a separation determination processof determining whether a probe 2 a is separated from a sample surface,based on a first detection signal and a second detection signal whichare output from a light detection unit 62. Specifically, the separationdetermination process of the determination unit 42E is to determine theseparation of the probe 2 a with respect to the sample surface, based onthe phase difference between the phase of vibration in the deflectiondirection or the twist direction of the cantilever 2 and the phase ofthe resonant frequency excited by the oscillation unit 3.

Hereinafter, the separation determination process according to the fifthembodiment will be described with reference FIGS. 20A and 20B.

In this method, the oscillation frequency is set to a cantileverresonant frequency. Then, the oscillation unit 3 causes the sample S andthe cantilever 2 to slightly vibrate relatively to each other at acantilever resonant frequency in the separating operation. In this case,the cantilever 2 is both-end supported in the state where the probe 2 ais in contact with the surface of the sample. For this reason, even ifbeing excited at the cantilever resonant frequency by the oscillationunit 3, the cantilever 2 does not resonate and vibrates withnon-resonance. Therefore, the phase difference between the phase ofvibration in the cantilever 2 and the phase of the oscillation frequencyexcited by the oscillation unit 3 is small.

On the other hand, when the probe 2 a and the surface of the sample areseparated from each other in the separating operation, since the probe 2a is away from the surface of the sample, the cantilever 2 is in acantilever state. Therefore, the cantilever 2 resonates by being excitedwith the cantilever resonant frequency by the oscillation unit 3.Accordingly, the phase difference between the phase of vibration in thecantilever 2 and the phase of the oscillation frequency excited by theoscillation unit 3 is approximately 90 degrees. That is, the phase ofvibration in the cantilever 2 has a phase delayed by 90 degrees from thephase of the oscillation frequency excited by the oscillation unit 3.

Therefore, in a case of moving from state where the probe 2 a is incontact with the surface of the sample to the state where the probe 2 ais separated from the surface of the sample, the phase differencebetween the phase of vibration in the cantilever 2 and the phase of theoscillation frequency excited by the oscillation unit 3 increases.Therefore, the determination unit 42E determines the separation of theprobe 2 a from the surface of the sample based on the phase differencebetween the phase of vibration in the deflection direction or the twistdirection of the cantilever 2 and the phase of the resonant frequencyexcited by the oscillation unit 3 in the separation operation. Forexample, the determination unit 42E determines that the probe 2 a isseparated from the surface of the sample when the phase differencebetween the phase of vibration in the deflection direction or the twistdirection of the cantilever 2 and the phase of the resonant frequencyexcited by the oscillation unit 3 exceeds a predetermined value in theseparating operation.

In this method, it may slightly vibrate the cantilever 2 at thecantilever resonant frequency in the deflection direction, or mayvibrate the cantilever 2 at the cantilever resonant frequency in thehorizontal direction. In addition, it may slightly vibrate the sample Sat the cantilever resonant frequency in the deflection direction, or mayvibrate the sample S at the cantilever resonant frequency in thehorizontal direction.

However, when the vibration slightly occurs in the deflection direction,the oscillation frequency is the cantilever resonant frequency of thecantilever 2 in the deflection direction. On the other hand, when thevibration slightly occurs in the horizontal direction, the oscillationfrequency is the cantilever resonant frequency of the cantilever 2 inthe horizontal direction.

In the separation determination process according to the fifthembodiment, the separation of the probe 2 a from the surface of thesample is determined under conditions that the deflection amountindicated by the first detection signal output from the light detectionunit 62 is within a first range and the twist direction indicated by thesecond detection signal output from the light detection unit 62 iswithin a second range.

As described above, the scanning probe microscope E according to thefifth embodiment includes the oscillation unit 3 that relativelyvibrates the sample S and the cantilever 2 at a predetermined frequencyin the separating operation and the determination unit 42E thatdetermines the separation of the probe 2 a from the surface of thesample based on the phase difference between the phase of vibration inthe deflection direction or the twist direction of the cantilever 2 andthe phase of the resonant frequency excited by the oscillation unit 3during the separating operation. Accordingly, since the scanning probemicroscope E is operated at the optimal separation distance at therespective measuring points of the sample S even in a case where thereis the adsorption power between the probe 2 a and sample S, it ispossible to achieve the measurement of the uneven shape in the samplesurface in the shortest time. Therefore, the scanning probe microscope Eis possible to improve the measurement efficiency of the uneven shape inthe sample surface.

As described above, the scanning probe microscope according to oneembodiment of the present disclosure does not determine whether theprobe 2 a is separated from the surface of the sample by separating itfrom the surface of the sample by a preset “separation distance” as inthe related art, but determines whether the probe 2 a and the surface ofthe sample are separated from each other while performing the separatingoperation. When it is determined that the probe and the surface of thesample are separated from each other, the separating operation isstopped. Then, the scanning probe microscope allows the probe to move tothe position above the next measuring point after stopping theseparating operation.

Here, when the deflection amount and the twist amount of the cantilever2 are within the predetermined range during the separating operation, amethod may be considered in which it is determined that the probe 2 a isnot in contact with the surface of the sample, that is, the probe 2 aand the surface of the sample are separated from each other. In thismethod, however, even when the deflection amount and the twist amount ofthe cantilever 2 are within the predetermined range, the probe 2 a andthe surface of the sample may be in contact with each other due to theadsorption power, and thus it is not possible to correctly detect thatthe probe and the surface of the sample are separated from each other.

On the other hand, according to the scanning probe microscope of oneembodiment of the present disclosure, it is possible to reliably detectthe separation of the probe 2 a from the surface of the sample byapplying the separation determination process according to any one ofthe first to fifth embodiments during the separating operation.

According to the above-described scanning probe microscope, it ispossible to avoid the probe 2 a from colliding with the sample byexecuting the separation determination process according to any one ofthe first to fifth embodiments during the separating operation in themovement up to the position above the next measuring point afterstopping the separating operation.

For example, according to the above-described scanning probe microscope,(1) the approaching operation is performed, and (2) it is determinedwhether the probe 2 a and the surface of the sample are in contact witheach other. According to the scanning probe microscope, when it isdetermining that the probe 2 a and the surface of the sample are incontact with each other, (3) the approaching operation is stopped andthe relative distance is measured. Then, according to the scanning probemicroscope, after the relative distance is measured, and (4) theseparating operation is started and whether the probe 2 a and thesurface of the sample are separated from each other is determined in theseparation determination process according to any one of the first tofifth embodiments during the separating operation. Then, according tothe scanning probe microscope, (5) when it is determined that the probe2 a and the surface of the sample are separated from each other, theseparating operation is stopped, and (6) the probe 2 a is moved up tothe position above the next measuring point. Here, the scanning probemicroscope determines in the separation determination process accordingto any one of the first to fifth embodiments whether the probe 2 a andthe surface of the sample are separated from each other while moving theprobe 2 a to the position above the next measuring point. Then, thescanning probe microscope continues the movement when it is determinedthat the probe 2 a and the surface of the sample are separated from eachother, and when the probe 2 a and the surface of the sample are not incontact with each other, returns to (5) described above to execute theseparating operation and start the separation determination processaccording to any one of the first to fifth embodiments.

Thus, the scanning probe microscope according to the embodiments of thepresent disclosure can avoid the probe 2 a from colliding with thesample in the movement to the position above the next measuring point.

In the separating operation of the first to fifth embodiments, thesample S is moved in the direction being separated from the probe 2 a.The probe 2 a may be moved in a direction being separated from thesample S in the separating operation.

The control devices 7, and 7B to 7E in the above-described embodimentsmay be implemented by a computer. In this case, it may be realized byrecording a program for achieving the functions thereof on acomputer-readable recording medium and causing a computer system to readand execute the program recorded on the recording medium. It is to benoted that the “computer system” used here is assumed to include an OSand hardware such as peripheral devices. In addition, the“computer-readable recording medium” refers to a portable medium such asa flexible disk, a magneto-optical disc, a ROM, or a CD-ROM, and astorage apparatus such as a hard disk embedded in the computer system.Further, the “computer-readable recording medium” is assumed to includea computer-readable recording medium for dynamically holding a programfor a short time as in a communication line when the program istransmitted via a network such as the Internet or a communicationcircuit such as a telephone circuit and a computer-readable recordingmedium for holding the program for a predetermined time as in a volatilememory inside the computer system serving as a server or a client. Inaddition, the above program may realize part of the above-describedfunctions, it may implement the above-described functions in combinationwith a program already recorded on the computer system, or theabove-described functions may be implemented using a programmable logicdevice such as a field programmable gate array (FPGA).

Although the embodiments of the present disclosure have been describedin detail with reference to the drawings, the specific configurationsare not limited to the embodiments and designs and the like may also beincluded without departing from the gist of the present disclosure.

The operations, procedures, steps, and stages of each process performedby an apparatus, system, program, and method shown in the claims,embodiments, or diagrams can be performed in any order as long as theorder is not indicated by “prior to,” “before,” or the like and as longas the output from a previous process is not used in a later process.Even if the process flow is described with reference to phrases such as“first” or “next” in the claims, embodiments, or diagrams, it does notnecessarily mean that the process must be performed in this order.

What is claimed is:
 1. A scanning probe microscope in which a probe isbrought into contact with a surface of a sample and the probeintermittently scans the surface of the sample, comprising: a cantileverhaving the probe at a tip of the cantilever; a driving unit configuredto perform a separating operation for separating one of the sample andthe probe from the other in a direction that the sample and the probecome apart each other, at a speed exceeding a response speed of thecantilever, from a state where the probe is in contact with the surfaceof the sample; a determination unit configured to determine that theprobe is separated from the surface of the sample in a case wherevibration of the cantilever at a predetermined amplitude is detected ata resonant frequency of the cantilever during the separating operation;and a driving control unit configured to stop the separating operationby the driving unit at a moment of time when the determination unitdetermines that the probe is separated from the surface of the sampleand relatively move the probe and the sample to a position where theprobe is located on a next measuring point of the sample.
 2. Thescanning probe microscope according to claim 1, wherein thepredetermined amplitude is a range smaller than displacement of thecantilever in a state where the probe is in contact with the surface ofthe sample, with reference to an amplitude due to thermal vibration in astate where no force is applied to the cantilever.
 3. A scanning probemicroscope in which a probe is brought into contact with a surface of asample and the probe scans the surface of the sample, comprising: acantilever having the probe at a tip of the cantilever; a driving unitconfigured to perform a separating operation for separating one of thesample and the probe from the other in a direction that the sample andthe probe come apart each other, at a speed not exceeding a responsespeed of the cantilever, from a state where the probe is in contact withthe surface of the sample; a determination unit configured to determinesseparation of the probe with respect to the surface of the sample, basedon a speed change in a deflection direction of the cantilever, duringthe separating operation; and a driving control unit configured to stopthe separating operation by the driving unit at a moment of time whenthe determination unit determines that the probe is separated from thesurface of the sample and relatively move the probe and the sample to aposition where the probe is located on a next measuring point of thesample.
 4. The scanning probe microscope according to claim 3, whereinthe determination unit determines that the probe is separated from thesurface of the sample in a case where a speed in the deflectiondirection of the cantilever reaches to a value equal to or less than apredetermined value.
 5. The scanning probe microscope according to claim3, wherein the determination unit determines that the probe is separatedfrom the surface of the sample in a case where a speed direction of thecantilever is reversed.
 6. A scanning probe microscope in which a probeis brought into contact with a surface of a sample and the probeintermittently scans the surface of the sample, comprising: a cantileverhaving the probe at a tip of the cantilever; a driving unit configuredto perform a separating operation for separating one of the sample andthe probe from the other, from a state where the probe is in contactwith the surface of the sample; a determination unit configured todetermine separation of the probe with respect to the surface of thesample, based on a change in amplitude of vibration in the cantilever ora change in vibration frequency of the vibration, during the separatingoperation; and a driving control unit configured to stop the separatingoperation by the driving unit at a moment of time when the determinationunit determines that the probe is separated from the surface of thesample and relatively move the probe and the sample to a position wherethe probe is located on a next measuring point of the sample.
 7. Ascanning probe microscope in which a probe is brought into contact witha surface of a sample and the probe intermittently scans the surface ofthe sample, comprising: a cantilever having the probe at a tip of thecantilever; a driving unit configured to perform a separating operationfor separating one of the sample and the probe from the other, from astate where the probe is in contact with the surface of the sample; anoscillation unit configured to relatively vibrate the sample and thecantilever at a predetermined frequency during the separating operation;a determination unit configured to determine separation of the probewith respect to the surface of the sample, based on a change inamplitude at the predetermined frequency in a deflection direction or atwist direction of the cantilever, during the separating operation; anda driving control unit configured to stop the separating operation bythe driving unit at a moment of time when the determination unitdetermines that the probe is separated from the surface of the sampleand relatively move the probe and the sample to a position where theprobe is located on a next measuring point of the sample.
 8. Thescanning probe microscope according to claim 7, wherein thepredetermined frequency is a non-resonant frequency of the cantilever,and the determination unit determines that the probe is separated fromthe surface of the sample in a case where a decrease amount of theamplitude at the non-resonant frequency in the deflection direction orthe twist direction of the cantilever during the separating operationexceeds a predetermined value.
 9. The scanning probe microscopeaccording to claim 7, wherein the predetermined frequency is a resonantfrequency of the cantilever in a state where the cantilever is incontact with the sample, and the determination unit determines that theprobe is separated from the surface of the sample in a case where adecrease amount of the amplitude in the deflection direction or thetwist direction of the cantilever during the separating operationexceeds a predetermined value.
 10. The scanning probe microscopeaccording to claim 7, wherein the predetermined frequency is a resonantfrequency of the cantilever, and the determination unit determines thatthe probe is separated from the surface of the sample in a case where anincrease amount of the amplitude at the resonant frequency in thedeflection direction or the twist direction of the cantilever during theseparating operation exceeds a predetermined value.
 11. A scanning probemicroscope in which a probe is brought into contact with a surface of asample and the probe intermittently scans the surface of the sample,comprising: a cantilever having the probe at a tip of the cantilever; adriving unit configured to perform a separating operation for separatingone of the sample and the probe from the other, from a state where theprobe is in contact with the surface of the sample; an oscillation unitconfigured to excites the cantilever at a resonant frequency during theseparating operation; a determination unit configured to determineseparation of the probe with respect to the surface of the sample, basedon a phase difference between a phase of vibration in a deflectiondirection or a twist direction of the cantilever and a phase of theresonant frequency excited by the oscillation unit, during theseparating operation; and a driving control unit configured to stop theseparating operation by the driving unit at a moment of time when thedetermination unit determines that the probe is separated from thesurface of the sample and relatively move the probe and the sample to aposition where the probe is located on a next measuring point of thesample.
 12. A probe scanning method of a scanning probe microscope inwhich a probe is brought into contact with a surface of a sample and theprobe intermittently scans the surface of the sample, the methodcomprising: a driving step, in a cantilever having the probe at a tip ofthe cantilever, of performing a separating operation for separating oneof the sample and the probe from the other in a direction that thesample and the probe come apart each other, at a speed exceeding aresponse speed of the cantilever, from a state where the probe is incontact with the surface of the sample; a determining step ofdetermining that the probe is separated from the surface of the samplein a case where vibration of the cantilever at a predetermined amplitudeis detected at a resonant frequency of the cantilever during theseparating operation; and a driving control step of stopping theseparating operation by the driving step at a moment of time when it isdetermined in the determining step that the probe is separated from thesurface of the sample and relatively moving the probe and the sample toa position where the probe is located on a next measuring point of thesample.
 13. A probe scanning method of a scanning probe microscope inwhich a probe is brought into contact with a surface of a sample and theprobe scans the surface of the sample, the method comprising: a drivingstep, in a cantilever having the probe at a tip of the cantilever, ofperforming a separating operation for separating one of the sample andthe probe from the other in a direction that the sample and the probecome apart each other, at a speed not exceeding a response speed of thecantilever, from a state where the probe is in contact with the surfaceof the sample; a determining step of determining separation of the probewith respect to the surface of the sample, based on a speed change in adeflection direction of the cantilever, during the separating operation;and a driving control step of stopping the separating operation by thedriving step at a moment of time when it is determined in thedetermining step that the probe is separated from the surface of thesample and relatively moving the probe and the sample to a positionwhere the probe is located on a next measuring point of the sample. 14.The probe scanning method according to claim 12, wherein the drivingcontrol step includes a step of determining whether the probe and thesurface of the sample are separated from each other in a case ofrelatively moving the probe and the sample to a position where the probeis located on a next measuring point of the sample.
 15. The probescanning method according to claim 13, wherein the driving control stepincludes a step of determining whether the probe and the surface of thesample are separated from each other in a case of relatively moving theprobe and the sample to a position where the probe is located on a nextmeasuring point of the sample.